Posts Tagged ‘first light’

The news is out, on the BBC and elsewhere, with the full coverage from ESA – first light results from all three of Herschel’s instruments, including the one I work on – SPIRE.

Image of the galaxy M66 taken with SPIRE at a wavelength of 250 microns compared to Spitzer image at 160 microns.

The images are superb! You can see far more structure in these images than in the best previously available even though SPIRE’s are at longer wavelengths. You can see structure in the dust distribution in these galaxies and, by comparing the three different colours SPIRE observes in, you can get some idea of the temperature distribution of the dust.

Also, the faint background blobs in these images are real, as they’re present at all three SPIRE wavelengths. These are background dusty galaxies which we expect SPIRE will be able to detect in great numbers. This promise is now fulfilled marvelously in the first images we’ve taken. These are the galaxies responsible for the Cosmic Infrared Background which encompasses half the energy generated in the universe since the Big Bang. It’s made up of light emitted by stars, and accreting supermassive back holes, which has been absorbed by dust and reradiated at these long far-IR wavelengths. It is the hidden history of the universe, something we have had little access to before now, but which SPIRE will now help us to understand in detail.

M74 images in all 3 SPIRE bands

HIFI, the high resolution spectrometer, also has released its first spectra, showing strong emission lines from gas involved in star formation in the DR21 molecular cloud.

Herschel was only launched about 7 weeks ago, and these observations are just a first quick look at what the instruments can do. There is a lot more tuning, calibration and refinement to be done before we can do real quantitative science with these instruments. For that reason to get decent data on anything at this stage is quite amazing. To get data of the quality seen in the SPIRE images, the PACS images you can find below and in the HIFI spectra is absolutely astounding.

SPIRE took its first light images on Wednesday. The data reached the instrument team this morning and is being first assessed for quality and then will be analysed over the weekend. Then, if we’re lucky, the rest of the SPIRE team might see the image next week…

PACS has seen first light, taking an image of the galaxy M51. I’ve not seen the image yet, it should be made public on Friday and I’m not allowed to see it before that, but the word is that it looks good, and the fast processed image is at least as good as the best images from Spitzer of this object.

We’ve now been told that the cryocover will be opening on Sunday, with first light data from the Herschel instruments coming down to us on Monday.

If the cryocover doesn’t open then that’s it – no science. It is what they call a ‘single point failure mode’. However, the cover’s mechanism has been extensively tested so it should work. In fact you can see a slow motion video of such a test here:

This is a test on an identical cryocover that had been kept closed for two years, and it worked perfectly. Still, some of us will be feeling quite nervous until we hear news of first light. Cross your fingers for us!